I've decided I want to learn how to write in shorthand. Which system should I use?

Being the nerd I am I have figured that learning shorthand would be fun/useful. A lot of my teachers lecture without powerpoint. They stand in front of the class, talk, and you write down what they say. I think shorthand would allow me to write what they say easier and then I can go home and transcribe them.

I’ve thought about taking a laptop to class, but I really don’t like having my laptop there, but some teachers don’t allow them. Plus, the odds are I’ll just end up watching the Youtube or something.

I know there are multiple types of shorthand available, from Pitman to Gregg, and so on. Which type should I try? One thing I want to be able to do is look at my original, shorthand notes in the future and be able to read what they say, so I don’t want to do that thing where you just drop the vowels and need to rush to transcribe, else you forget what you wrote.

Thanks!